I hate this. Not that it's any consolation but I've been done and ended up with worthless junk in a similar manner a few times.
Why do dealers do this? I know its greed but surely they get a rep and no one buys from them after a while. This keeps me away from some fairs on this side of the pond as I'll remember the dealer who did me and I don't want to see him again. These aren't mistakes, it's robbery, pure and simple.
Troy, I'm sorry mate but you're not alone.
Otter, I agree with you. I'd like to name these f*****s and help put them out of business. Every time I buy something now I'm going to ask for a card or contact details. I'll invite them round for afternoon tea at my house.